Updates of Semileptonic Results for Summer 2004
The changes of this update with respect to the previous status are
described here. A writeup is being finalized
for publication as hep-ex, once it appears, we will update this
webpage with a hyperlink.
All analyses are rescaled to a common set of input parameters defined
in common.param.
Spreadsheet with the breakdowns of the errors can be found for
incl |Vub| and excl |Vub|.
nada
Exclusive Branching Fraction: B0 -> Dlnu
This is a one-dimensional fit for the average branching fraction.
| Experiment |
BF (rescaled) [%] |
Parameters |
Remarks |
| ALEPH |
2.39 +/- 0.20+/- 0.50 |
input parameters |
Phys.Lett.B395:373-,1997 |
| CLEO |
2.10+/- 0.13+/- 0.17 |
input parameters |
Phys.Rev.Lett.82:3746-,1999 |
| BELLE |
2.18+/- 0.12+/- 0.39 |
input parameters |
Phys.Lett.B526:258-268,2002 |
| Average
| 2.13+/- 0.20
| chi2/dof = 0.3/2 (CL = 0.864)
| eps gif |
nada
Exclusive Branching Fraction: B0 -> D*lnu
This is a one-dimensional fit for the average branching fraction.
| Experiment |
BF (rescaled) [%] |
Parameters |
Remarks |
| ALEPH |
5.78 +/- 0.26 +/- 0.36 |
input parameters
| Phys.Lett.B395:373-,1997 |
| OPAL (excl) |
5.50 +/- 0.19 +/- 0.40 |
input parameters |
Phys.Lett.B482:15-,2000, exclusive reco. |
| OPAL (partial reco) |
6.19 +/- 0.27 +/- 0.58 |
input parameters |
Phys.Lett.B482:15-,2000, partial reco. |
| DELPHI (partial reco) |
5.03 +/- 0.13 +/- 0.36 |
input parameters
| Phys.Lett.B510:55-,2001, partial reco. |
| BELLE |
4.72 +/- 0.23 +/- 0.42 |
input parameters
| Phys.Lett.B526:247-,2002 |
| CLEO |
6.22 +/- 0.19 +/- 0.39 |
input parameters
| Phys.Rev.Lett.89:081803,2002 |
| DELPHI (excl) |
5.80 +/- 0.22 +/- 0.47 |
input parameters |
Eur.Phys.J.C33:213-,2004, exclusive reco. |
| BABAR |
4.85 +/- 0.07 +/- 0.34 |
input parameters |
hep-ex/0408027 |
| Average |
5.33 +/- 0.20 |
chi2/dof = 14.2/7 (CL = 0.047) |
eps gif |
nada
Inclusive Semileptonic Branching Fraction for B+/B0 Admixture: B -> Xlnu
This is a one-dimensional fit for the average branching fraction. Note
that the contribution from B -> Xulnu is included here.
| Experiment |
Rescaled Value [%] |
Input |
Remarks |
| ARGUS (e tag) |
09.76 +/- 0.50 +/- 0.39 |
input parameters
| Phys.Lett.B318:397-, 1993 |
| BABAR (breco tag) |
10.40 +/- 0.50 +/- 0.46 |
input parameters
| conference paper (hep-ex/0204001) |
| BELLE (l tag) |
10.97 +/- 0.12 +/- 0.49 |
input parameters
| Phys.Lett.B547:181-, 2002 |
| BABAR (e tag) |
10.92 +/- 0.18 +/- 0.29 |
input parameters
| Phys.Rev.D67:031101, 2003 |
| BELLE (breco) |
11.19 +/- 0.20 +/- 0.31 |
input parameters
| breco-tag, preliminary |
| CLEO (l tag, 2003) |
10.91 +/- 0.08 +/- 0.30 |
input parameters
| e-tag, preliminary, superceedes PRL 76:1570 (1996) |
| Average |
10.90 +/- 0.23 |
chi2/dof = 5.0/5 (CL = 0.421) |
eps gif |
nada
Inclusive Partial Semileptonic Branching Fraction for B+/B0 Admixture: B -> Xlnu
This is a one-dimensional fit for the average partial branching
fraction (the electron has momentum p > 0.6 GeV in the Upsilon(4S)
center-of-mass system). Note that the contribution from B ->
Xulnu is included here.
| Experiment |
Rescaled Value [%] |
Input |
Remarks |
| BELLE (l tag) |
10.31 +/- 0.11 +/- 0.47 |
input parameters
| Phys.Lett.B547:181-, 2002 |
| BABAR (e tag) |
10.37 +/- 0.06 +/- 0.23 |
input parameters
| Phys.Rev.D67:031101, 2003 |
| CLEO (l tag) |
10.23 +/- 0.08 +/- 0.21 |
input parameters
| hep-ex/0403053 and C.J. Stepaniak thesis |
| Average |
10.29 +/- 0.18 |
chi2/dof = 0.22/2 (CL = 0.896) |
eps gif |
Exclusive |Vcb| F(1)
This table and the plots in the last row document the two-dimensional
simultaneous fit to |Vcb|*F(1) and rho2. Note: The averages
are determined in a two-dimensional fit that is completely systematics
limited.
| Experiment |
|Vcb| F(1) (rescaled) [10-3] |
rho2 (rescaled) |
Correlation (stat/syst/total) |
Parameters |
Remarks |
| ALEPH |
33.7 +/- 2.1 +/- 1.6 |
0.75 +/- 0.25 +/- 0.37 |
0.94/0.60/0.72 |
input parameters
| Phys.Lett.B395:373-,1997 |
| OPAL (partial reco) |
38.5 +/- 1.2 +/- 2.4 |
1.25 +/- 0.14 +/- 0.39 |
0.77/0.70/0.71 |
input parameters
| Phys.Lett.B482:15-,2000 |
| OPAL (excl) |
39.3 +/- 1.6 +/- 1.8 |
1.49 +/- 0.21 +/- 0.26 |
0.95/0.44/0.65 |
input parameters
| Phys.Lett.B482:15-,2000 |
| DELPHI (partial reco) |
36.9 +/- 1.4 +/- 2.5 |
1.50 +/- 0.14 +/- 0.37 |
0.94/0.77/0.79 |
input parameters
| Phys.Lett.B510:55-,2001 |
| BELLE |
36.4 +/-1.9 +/- 1.9 |
1.45 +/- 0.16 +/- 0.20 |
0.91/0.68/0.78 |
input parameters
| Phys.Lett.B526:247-,2002 |
| CLEO |
43.6 +/- 1.3 +/- 1.8 |
1.61 +/- 0.09 +/- 0.21 |
0.87/0.62/0.67 |
input parameters
| Phys.Rev.Lett.89:081803,2002 |
| DELPHI (excl) |
38.8 +/- 1.8 +/- 2.1 |
1.32 +/- 0.15 +/- 0.33 |
0.89/0.50/0.58 |
input parameters
| Eur.Phys.J.C33:213-,2004 |
| BABAR |
35.3 +/- 0.3 +/- 1.6 |
1.29 +/- 0.03 +/- 0.27 |
0.56/0.73/0.72 |
input parameters
| hep-ex/0408027 |
| Average |
37.7 +/- 0.9 |
1.56 +/- 0.14 |
0.73/0.56/0.57 |
chi2/dof = 26.9/14 |
eps 1 gif 1
eps 2 gif 2 |
With F(1) = 0.91 +/- 0.04theo, this yields
|Vcb| = (41.4 +/-1.0exp +/- 1.8theo)10-3
nada
Exclusive |Vcb|G(1)
This table and the plots in the last row document the two-dimensional
simultaneous fit to |Vcb|*G(1) and rho2. Note: The averages
are determined in a two-dimensional fit.
| Experiment |
|Vcb| G(1) (rescaled) [10-3] |
rho2 (rescaled) |
Correlation (stat/syst/total) |
Parameters |
Remarks |
| ALEPH |
39.9+/- 10.0+/- 6.4 |
1.01+/- 0.98+/- 0.37 |
0.98/0.99/0.96 |
input parameters |
Phys.Lett.B395:373-,1997 |
| CLEO |
44.6+/- 5.8+/- 3.5 |
1.27+/- 0.25+/- 0.14 |
0.95/0.98/0.96 |
input parameters |
Phys.Rev.Lett.82:3746-,1999 |
| BELLE |
41.6+/- 4.4 +/- 5.2 |
1.12+/- 0.22+/- 0.14 |
0.96/0.96/0.92 |
input parameters |
Phys.Lett.B526:258-268,2002 |
| Average |
42.0+/- 3.7 |
1.16+/- 0.16 |
0.93/0.91/0.90 |
chi2/dof = 0.3/4 |
eps 1 gif 1
eps 2 gif 2
|
With G(1)=1.04+/-0.06theo, this gives |Vcb| = (40.4 +/-3.6exp +/-2.3theo) 10-3
nada
|Vcb| from Inclusive Semileptonic Decays B -> Xlnu
In the past,
the measurement of the branching fraction was corrected for the
contribution of B->u l nu and used to determine |Vcb|. That approach
was theoretically limited (at the time) because of the imprecise
knowledge of higher-order parameters entering the relation between the
width and |Vcb|.
In the meantime, experimental progress has allowed the development
of "global fits" using data from measurements of various moments of
hadronic mass and lepton energy in inclusive semileptonic B->X l nu
decays.
Several groups have published along these lines,
The following table summarizes |Vcb| derived with the two most
recent approaches. More information is available from the preprints
cited above.
| Collaboration |
|Vcb|*1e3 |
References |
Remarks |
| BABAR collaboration |
41.4+/-0.4(exp) +/-0.4(HQE) +/-0.6(theo) |
Phys.Rev.Lett.93:011803,2004 |
global fit to all data |
| CLEO collaboration |
42.4+/-0.8 |
Alex Smith, BEACH 2004 |
|
| Bauer, et al |
41.9 +/-0.6 +/-0.1(tau(B)) |
hep-ph/0408002 |
global fit to all data |
nada
|Vub| in inclusive semileptonic B decays
The errors in the table are uncorrelated (statistical and experimental
systematic) and correlated (experimental and theoretical; the errors
for each measurement does not include the common error of 4.8% from
the rate to |Vub|, though the final average does include
that error). The procedure for this average is documented in the
writeup. The average is currently based on the results from the
Upsilon(4S), i.e. from the BABAR, BELLE, and CLEO collaborations.
The derivation of the 'theoretical' error (from the uncertainty of
the shape function and its parameters) relies on the measurement of
the photon spectrum in the process B -> s gamma (see this
webpage for more information and links to additional material).
The CLEO and BELLE collaboration have provided information in the form
of two preprints authored by a subset of the collaborations:
A combination of these results has not yet been achieved, but is
planned for a future update. Until then, the main average will be
based on the more precise measurement of the BELLE collaboration.
| Experiment |
Value [10-3] |
Parameters |
References |
Remarks |
| ALEPH |
4.12 +/- 0.67 +/- 0.71 |
|
|
neural net (not used in average) |
| L3 |
5.70 +/- 1.00 +/- 1.40 |
|
|
cut and count (not used in average) |
| DELPHI |
4.07 +/- 0.65 +/- 0.61 |
|
|
mX (not used in average) |
| OPAL |
4.00 +/- 0.71 +/- 0.71 |
|
|
neural net (not used in average) |
| CLEO (endpoint) |
4.69 +/- 0.23 +/- 0.63 |
input
| Phys.Rev.Lett.88:231803,2002 |
2.2 < p < 2.6, rescaled and fu from BELLE |
| BELLE sim. ann. (m_{X}, Q^{2}) |
4.75 +/- 0.46 +/- 0.46 |
input
| Phys.Rev.Lett.92:101801,2004 (hep-ex/0311048) |
mX - Q2, tag with annealing method |
| BELLE (endpoint) |
4.46 +/- 0.23 +/- 0.61 |
input
| BELLE-CONF-0325 |
2.3 < p < 2.6, fu from BELLE |
| BABAR (endpoint) |
4.40 +/- 0.15 +/- 0.44 |
input
| hep-ex/0408075 |
2.0 < p < 2.6, fu uncertainty from BELLE |
| BABAR m_{X} |
5.22 +/- 0.30 +/- 0.43 |
input
| preliminary (hep-ex/0408068) |
mX, BRECO tag |
| BABAR (m_{X}, Q^{2}) |
5.18 +/- 0.52 +/- 0.42 |
input
| preliminary (hep-ex/0408068) |
(mX, Q2), BRECO tag |
| BABAR (E_{l}, Q^{2}) |
4.99 +/- 0.34 +/- 0.51 |
input
| preliminary (hep-ex/0408045) |
(El, Q2) |
| BELLE B_{reco} (m_{X}, Q^{2}) |
5.54 +/- 0.65 +/- 0.54 |
input
| preliminary (ICHEP-talk) |
mX - Q2, tag with B_{reco} |
| Average |
4.70 +/- 0.44 |
chi2/dof = 6.7/7 (CL = 0.465) |
|
eps gif
all: eps gif
|
nada
|Vub| from exclusive decays
Measurements using the entire q2 range
| Experiment |
Mode |
BF [10-4] |
|Vub| (rescaled) [10-3] |
Reference |
| CLEO |
B0-> rho- l+ nu |
2.69 +/-0.41 +0.35/-0.40 +/-0.50 |
3.24 +/-0.25 +0.21/-0.24 +/-0.58 |
Phys. Rev. D 61, 052001 (2000) |
| BABAR |
B0-> rho- l+ nu |
3.29 +/-0.42 +/-0.47 +/-0.60 |
3.59 +/-0.23 +/-0.26 +/-0.66 |
Phys. Rev. Lett. 90, 181801 (2003) |
| Belle |
B+-> omega l+ nu |
1.3 +/-0.4 +/-0.2 +/-0.3 |
3.1 +/-0.2 +/-0.2 +/-0.6 |
submitted to Phys. Rev. Lett. |
Measurements using different bins of q2 (0-8-16
GeV2)
| Experiment |
Mode |
BF [10-4] |
|Vub| [10-3] |
Reference |
| CLEO |
B0-> pi- l+ nu |
1.33 +/-0.18 +/-0.11 +/-0.01 +/-0.07 |
2.88 +/-0.55 +/-0.30 +0.45/-0.35 +/-0.18 |
Phys. Rev. D 68, 072003 (2003) |
| CLEO |
B0-> rho- l+ nu |
2.17 +/-0.34 +0.47/-0.54 +/-0.41 +/-0.01 |
3.34 +/-0.32 +0.27/-0.36 +0.50/-0.40 |
Phys. Rev. D 68, 072003 (2003) |
| Belle |
B0-> pi- l+ nu |
1.76 +/-0.28 +/-0.20 +/-0.03 |
3.90 +/-0.71 +/-0.23 +0.62/-0.48 |
preliminary (hep-ex/0408145) |
| Belle |
B0-> rho- l+ nu |
2.54 +/-0.78 +/-0.85 +/-0.30 |
|
preliminary (hep-ex/0408145) |
| BABAR |
B0-> pi- l+ nu |
1.46 +/-0.27 +/-0.28 |
|
preliminary (ICHEP04
talk) |
|Vub| is extracted from the partial branching ratio in
the region q2>16 GeV2 using LQCD
calculations. For pi l nu, the average of the following analyses is
used: FNAL '01, JLQCD, APE and UKQCD '00. For rho l nu, the UKQCD
calculation is used. ( See Phys. Rev. D 68, 072003 (2003) and
references therein. )
Last update: 2004/10/02 Urs Langenegger and Christoph Schwanda
